old two handled shower broken.

Attached are a couple of photos showing the present state of my shower valve (tap) system. I'm in Costa Rica and things get built piece meal by various different people and with whatever materials happen to be available locally. I have a solar hot water heater on my roof that feeds the whole house as well as a "suicide shower" instant hot water shower head. I had a two handle system with a faucet and a plunger that regulated the flow of water either to the faucet or the shower head. There is no rough valve as far as I can tell. The pipes are PVC. The faucet broke off the flow control/taps piece of metal. I don't need the faucet since I have only a stand up shower. I'd like to plug that hole and find some way to direct the water up to the shower head. That would be the cheapest solution. Finding the various more modern and fancier parts here is impossible and ordering from the Internet is difficult since most places don't ship to Costa Rica. I don't need a whole new shower set with shower head, taps, etc. That would be too complicated for a local "plumber" to deal with. How can I create a way to force the flow of the water up to the shower head and block off the hole where the faucet used to be?